import  sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

if __name__ == '__main__':
    app=QApplication(sys.argv)
    label=QLabel("<font color=red size=128> <b>窗口5秒钟消失 </b></font>")
    label.setWindowFlags(Qt.SplashScreen|Qt.FramelessWindowHint)
    label.show()
    QTimer.singleShot(5000,app.quit)
    sys.exit(app.exec_())